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A trilobite fossil from the Ordovician period, which lasted from about 485 to 443 million years ago. A new analysis of marine fossils from most of the past half-billion years shows the usual rules of body size evolution change during mass extinctions and their recoveries.
A trilobite fossil from the Ordovician period, which lasted from about 485 to 443 million years ago. A new analysis of marine fossils from most of the past half-billion years shows the usual rules of body size evolution change during mass extinctions and their recoveries.
Since the 1980s, evolutionary biologists have debated whether mass extinctions and the recoveries that follow them intensify the selection criteria of normal times - or fundamentally shift the set of traits that mark groups of species for destruction. The new study finds evidence for the latter in a sweeping analysis of marine fossils from most of the past half-billion years.
Whether and how evolutionary dynamics shift in the wake of global annihilation has "profound implications not only for understanding the origins of the modern biosphere but also for predicting the consequences of the current biodiversity crisis," the authors write.
"Ultimately, we want to be able to look at the fossil record and use it to predict what will go extinct, and more importantly, what comes back," said lead author Pedro Monarrez, a postdoctoral scholar in Stanford's School of Earth, Energy & Environmental Sciences (Stanford Earth). "When we look closely at 485 million years of extinctions and recoveries in the world's oceans, there does appear to be a pattern in what comes back based on body size in some groups."
Comment: What did NOAA and NASA have to gain as gatekeepers and producers of doctored information?
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